1. Technological Field
This disclosure relates to sensors for various digital chipsets and integrated circuits (IC). More specifically, this disclosure relates to temperature sensing at various locations across digital ICs.
2. Related Art
Modern very large scale integration (VLSI) chipsets and SoCs (System on Chip) implement various types of sensors throughout an IC. Accurate and reliable temperature sensing across the digital chips is an important element in thermal management and mitigation schemes for ICs. Such plans can be a key factor in power consumption and circuit performance. Temperature sensing can be a critical aspect of IC performance, where 1° C. error can translate to as much as one percent performance loss in mobile system modems (MSM). Some thermal sensors can include a main sensor with multiple passive remote sensors spread throughout the IC. Remote sensors can provide a sensor output indicative of temperature. A controller can periodically poll the remote sensors to determine temperature variations across the IC and provide the sensor outputs to a main sensor. The requirement for more sensors increases with IC complexity and capability, but the number of sensors implemented in an IC is limited by ever-shrinking size constraints of ICs.
Voltage controlled oscillators (VCO) can be useful as data converters due to the low power requirements, high speed, and ease of integration into ICs. Such VCOs can be configured to receive and aggregate the sensor outputs for use by a controller. However, VCOs may have a nonlinear frequency response to temperature, and therefore can require additional circuitry to address such nonlinearity to measure temperature more reliably.